The time stamps in the edit history list for any talk page appear in UTC, or in the local time that is set in your preferences. If you did not adjust the time in your preferences, then the times in the edit history list are in UTC.

Talk page times should always be in UTC. So be sure to use UTC time when using this unsigned template. Adjust the time, if necessary, using the difference you designated between the server UTC time and local time. If this is too difficult to figure out, or you are in a hurry, then leave out the time, and only put in the date.